common positioning errors in digital panoramic radiographies taken in mashhad dental school

Introduction: the present study was aimed at evaluating common positioning errors on panoramic radiographs taken in the radiology department of mashhad dental school. materials and methods: the study sample included 1,990 digital panoramic radiographs taken in the radiology department of mashhad dental school by a planmeca promax (planmeca oy, helsinki, finland), during a 2year period (2010–2012). all radiographs, according to dentition and sex, were evaluated for positioning errors. results: there were 1,927 (96.8%) panoramic radiographs with one or more errors. while the number of errors in each image varied between one and five, most images had one error (48.4%). the most common error was that the tongue was not in contact with the hard palate (94.8%). "open lips" was an error not seen in any patients. conclusions:positioning errors are common in panoramic radiographies. the most common error observed in this study was a failure to place the tongue on the palate. this error and the other errors reported in this study can be reduced by training the technicians and spending little more time for patient positioning and more effective communication with the patients.